Copper Concentrations in Tidal Creeks and Estuaries of the Eastern Shore and the Relationship to Plasticulture and Copper-based Crop Protectants

by Klawiter, Kathryn Alyce

Abstract (Summary)

This project investigates the effect of plasticulture and
copper-based crop protectants on water quality on the
Eastern Shore of Virginia. Water and sediment copper
concentrations in both plasticulture and non-plasticulture
containing watersheds were measured to determine the scope
of copper in Eastern Shore tidal creeks. Runoff from a
variety of land-uses including agricultural,
plasticultural, residential and natural areas were
collected and measured for copper to determine where
copper-containing runoff originates.
Copper concentrations in plasticulture impacted tidal
creeks were higher than background (0 - 3 ug/L) only in
spikes, during or immediately after runoff-producing
rainfall events. These spikes registered as high as
263 ug/L total copper, or 127 ug/L dissolved copper.
Plasticulture and copper-based crop protectants were
affirmed as the cause of these spikes because control
watersheds indicated no high copper spikes.
Runoff from different land-uses verify that copper
is present in high concentrations only in runoff from
fields engaged in plasticulture and using copper-based
crop protectants. Sediment copper concentrations were
found to be within the natural range, but exhibited some
variability based on proximity to agricultural copper
inputs.